Exterior surface configuration of vehicular taillight



FIG. 1 is a perspective view of an exterior surface configuration of a vehicular taillight showing my present design;

FIG. 2 is a front view thereof;

FIG. 3 is a left view thereof; and,

FIG. 4 is a top plan view thereof. 

I claim, the ornamental design for an exterior surface configuration of a vehicular taillight, as shown and described. 